TY - JOUR
T1 - A forward-adjoint operator pair based on the elastic wave equation for use in transcranial photoacoustic computed tomography
AU - Mitsuhashi, Kenji
AU - Poudel, Joemini
AU - Matthews, Thomas P.
AU - Garcia-Uribe, Alejandro
AU - Wang, Lihong V.
AU - Anastasio, Mark A.
N1 - ∗Received by the editors December 12, 2016; accepted for publication (in revised form) May 15, 2017; published electronically November 16, 2017. http://www.siam.org/journals/siims/10-4/M110761.html Funding: The work of the authors was supported in part by NIH awards EB01696301 and 5T32EB01485505 and NSF award DMS1614305. †Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130 (kenji.m. [email protected], [email protected], [email protected], [email protected], anastasio@ wustl.edu). ‡California Institute of Technology, Pasadena, CA 91125-0001 ([email protected]).
PY - 2017
Y1 - 2017
N2 - Photoacoustic computed tomography (PACT) is an emerging imaging modality that exploits optical contrast and ultrasonic detection principles to form images of the photoacoustically induced initial pressure distribution within tissue. The PACT reconstruction problem corresponds to an inverse source problem in which the initial pressure distribution is recovered from measurements of the radiated wavefield. A major challenge in transcranial PACT brain imaging is compensation for aberrations in the measured data due to the presence of the skull. Ultrasonic waves undergo absorption, scattering, and longitudinal-to-shear wave mode conversion as they propagate through the skull. To properly account for these effects, a wave-equation-based inversion method should be employed that can model the heterogeneous elastic properties of the skull. In this work, a forward model based on a finite-difference time-domain discretization of the three-dimensional elastic wave equation is established and a procedure for computing the corresponding adjoint of the forward operator is presented. Massively parallel implementations of these operators employing multiple graphics processing units are also developed. The developed numerical framework is validated and investigated in computer-simulation and experimental phantom studies whose designs are motivated by transcranial PACT applications.
AB - Photoacoustic computed tomography (PACT) is an emerging imaging modality that exploits optical contrast and ultrasonic detection principles to form images of the photoacoustically induced initial pressure distribution within tissue. The PACT reconstruction problem corresponds to an inverse source problem in which the initial pressure distribution is recovered from measurements of the radiated wavefield. A major challenge in transcranial PACT brain imaging is compensation for aberrations in the measured data due to the presence of the skull. Ultrasonic waves undergo absorption, scattering, and longitudinal-to-shear wave mode conversion as they propagate through the skull. To properly account for these effects, a wave-equation-based inversion method should be employed that can model the heterogeneous elastic properties of the skull. In this work, a forward model based on a finite-difference time-domain discretization of the three-dimensional elastic wave equation is established and a procedure for computing the corresponding adjoint of the forward operator is presented. Massively parallel implementations of these operators employing multiple graphics processing units are also developed. The developed numerical framework is validated and investigated in computer-simulation and experimental phantom studies whose designs are motivated by transcranial PACT applications.
KW - Elastic wave equation
KW - Image reconstruction
KW - Photoacoustic computed tomography
KW - Transcranial imaging
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U2 - 10.1137/16M1107619
DO - 10.1137/16M1107619
M3 - Article
C2 - 29387291
AN - SCOPUS:85039753054
SN - 1936-4954
VL - 10
SP - 2022
EP - 2048
JO - SIAM Journal on Imaging Sciences
JF - SIAM Journal on Imaging Sciences
IS - 4
ER -